Create a default tmux session only when none defined in tmux.conf

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Support $PYTHONUSERBASE per PEP 370

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
First zsh config changes
Add bundle exec alias
zsh config
Conf history changes
Source ~/.zshrc.local if it exists
Support chruby
[zsh] add direnv, move chruby config to zshenv
Use `whoami` instead of $USER

See https://github.com/tpope/vim-dispatch/issues/64 for details